Effects in an Octahedron

FIGURE 15.2. An interaction diagram tor the tt components in a MLsCO complex where L is an arbitrary a donor. 

When the ligand has only one tt acceptor function, then one component of t2g is stabilized. A case in point is the carbene ligand, 15.20 it has a filled o donor and empty tt acceptor function (Section 8.8) which is available for bonding to one member of the t2g set. One example is provided by 15.21. When the energy gap and 

The substitution of two or more tt acceptor ligands at the metal will stabilize two or all three members of the metal t2g set. For example, in Cr(C0)6, symmetry-adapted linear combinations of the 12 tt levels yields one of (2g symmetry. Therefore, metal. vz, vz, and xy are stabilized. 

FIGURE 15.3. Interaction diagrams lor two possible ct)n1oimations in a complex. Only the tt inleiactions arc illustrated. 

15 TRANSmON METAL COMPLEXES A STARTING POINT AT THE OCTAHEDRON 

Contour plots of the it and n orbitals in CH2Cr(CO)s, (a) and (b), respectively, along with the corresponding orbitals in CH2Ta-(CH3)3, (c) and (d), respectively. 

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Figure 1.8 The effect of a Jahn-Teller distortion on the d-electron energy levels of a B-site cation in an octahedron...

The Cupric, Cu2+ or Cu(II) State, 3d9 The most important and stable oxidation state for copper is divalent. There is a well-defined aqueous chemistry of the Cu2+ ion, which generates the familiar blue solution when complexed with water. A large number of copper coordination compounds exist and these have been studied extensively. A strong Jahn-Teller distortion is associated with the 3d9 electronic configuration of this ion. This implies that a regular tetrahedron or octahedron about the Cu2+ ion is never observed, except in the rare occurrence of a dynamic Jahn-Teller effect. The tetragonal distortion about an octahedron can lead to a square-planar coordination which is often observed in Cu(II) oxides. 

This effect is observed, for example, in inorganic complexes, where the metal ion is octahedral and the six ligands might be expected to occupy positions at equal distances at the corners of an octahedron, in an ideal structure. In the actual structure however, the octahedron may be distorted with four ligands in a square planar coordination and the remaining two ligands at opposite corners at longer distances. Many oxides exhibit Jahn-Teller distortions. 

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